97 GTS runs then dies

[Gwstaudy]

Alright so I’ve posted on here before about the issues with my ski and it never really got resolved so here I am again. I’ve made good progress on the rest of my pwc but it still struggles to run. I pull the choke and it’ll start fine and I give it a few seconds then let go of the choke and it’ll run for 10 seconds or so then die. To answer the questions everyone will ask: carb has been fully rebuilt with only oem parts and I’ve checked it to make sure it’s done correctly, it has good pop off pressure, the fuel pump can hold a few psi indefinitely, I replaced the fuel filter, I replaced the fuel petcock and it isn’t leaky, all fuel lines have been replaced, and I’ve got the carb set to factory settings, I’ve also ran a hose to another fuel source and nothing changes. Mind you this engine is also fully rebuilt. It’s got a new crank, new pistons and overbored cylinders and everything between.

I have some suspicion that my fuel lines could be the culprit (they are the transparent kind you can get from a ton of places online) as I was told they don’t allow the fuel pump to work properly so I changed out my pulse line to higher quality stuff and it worked better but still no running. Can anyone help?

-Update- I replaced the fuel lines with better quality line and it helped a little but it still has the same issue.

 

[burtshaver2021]

I seen your post yesterday, wasn’t going to answer in hopes someone with more experience may answer. The fact that it starts with the choke and then runs for 10 seconds after letting the choke off says it’s not getting fuel. Not 100 percent sure exactly what component is starving it of fuel but…. What is the compression? You say you’ve by passed the selector valve and fuel filter with same results? I have a mikuni carb article that explains what part of the carb provides fuel at a particular throttle position, I will have a read through it when I get time. Have you tried pulling the throttle quickly say to 5000 rpm within that first 10 seconds that it runs?

 

[burtshaver2021]

I read through your old post, I would recommend posting to your old post. It is the same issue and all the information is already there. When I was reading through the post I noticed that you’ve had the carbs apart 3 or 4 times, also noticed that your buying almost all of your parts off amazon, and that last time you checked you had 130 to 140 pounds of compression and that it always runs when you add fuel and or pull the choke so timing is fine, everything is fine except fuel. If you haven’t checked it lately, just check that compression just to be sure, and even though you know it was mikuni off Amazon I would just bite the bullet and buy the back to OEM kit from OSD, follow @mikidymac rebuild thread. If it runs when you put fuel in plug holes but won’t run on its own, it’s fuel. Good luck

 

[Gwstaudy]

I seen your post yesterday, wasn’t going to answer in hopes someone with more experience may answer. The fact that it starts with the choke and then runs for 10 seconds after letting the choke off says it’s not getting fuel. Not 100 percent sure exactly what component is starving it of fuel but…. What is the compression? You say you’ve by passed the selector valve and fuel filter with same results? I have a mikuni carb article that explains what part of the carb provides fuel at a particular throttle position, I will have a read through it when I get time. Have you tried pulling the throttle quickly say to 5000 rpm within that first 10 seconds that it runs?

Yeah I understand that, this thing is a pain. Yes I’ve bypassed the fuel selector and and filter. I’m not sure on what the compression is but I know it’s good as nothings changed since the test. I have revved the engine up and that doesn’t kill it so that tells me it’s high speed and everything is fine. Today I pulled out the carb and I checked and it appears my low speed jet is clear but somewhere beyond it must be clogged because nothing seems to flow through. So I think that could be the issue because that would affect its ability to run at idle. I’m just not sure how to clear whatever plugging it because I’ve tried multiple things like carb cleaner and soaking it. Maybe it just needs more? Otherwise I’ve checked the rest of the carb and it is getting fuel pumped to it and fuel is making to the jets just not passing that point apparently.

 

[burtshaver2021]

I would just verify that compression, just as a safety precaution to avoid chasing your tail just in case, once you’ve verified the compression I would take the carb apart again and check the sizing on the jets, if they are stock size, I would buy that back to OEM rebuild kit from OSD marine. I suppose if you don’t mind pulling it apart more than one more time you could also verify that fuel is coming out the tiny holes in the carb throat while spraying carb cleaner in the pilot jet orfice with the jet out, almost positive that’s the route the fuel takes up to 1/4 throttle. If all that checks out I would buy the kit. I’m no expert that’s for sure but I’ve had 3 machines that have had good compression and spark, bought the back to OEM kits, followed @mikidymac thread and they run. Let me know how it turns out

 

[burtshaver2021]

Just a tip I got on here, when you’re spraying the carb cleaner through the pilot circuit you can thread the low speed screw in one turn. I guess that helps get the carb cleaner through

 

[Gwstaudy]

I would just verify that compression, just as a safety precaution to avoid chasing your tail just in case, once you’ve verified the compression I would take the carb apart again and check the sizing on the jets, if they are stock size, I would buy that back to OEM rebuild kit from OSD marine. I suppose if you don’t mind pulling it apart more than one more time you could also verify that fuel is coming out the tiny holes in the carb throat while spraying carb cleaner in the pilot jet orfice with the jet out, almost positive that’s the route the fuel takes up to 1/4 throttle. If all that checks out I would buy the kit. I’m no expert that’s for sure but I’ve had 3 machines that have had good compression and spark, bought the back to OEM kits, followed @mikidymac thread and they run. Let me know how it turns out

Yeah that’s the problem is that nothing is coming out of the tiny holes in the carb throat. I’ve tried spraying carb cleaner and what not but it still seems clogged

 

[burtshaver2021]

That’s good news. That the problem then. Have you tried threading the low speed screw in yay one turn instead of having it right out? Spray the carb cleaner then some compressed air, repeat till you see flow. Maybe try blowing air across the tiny holes to create a vacuum while spraying as well. Get that cleaned and keep your fingers crossed

 

[Gwstaudy]

That’s good news. That the problem then. Have you tried threading the low speed screw in yay one turn instead of having it right out? Spray the carb cleaner then some compressed air, repeat till you see flow. Maybe try blowing air across the tiny holes to create a vacuum while spraying as well. Get that cleaned and keep your fingers crossed

Yeah so I’ve been looking at the carb rebuild sticky and I’m seeing there’s supposed to be one large hole and three small ones. Except I can’t seem to find the small ones. That’s because if they are where I believe they are they’re fully plugged with some white substance. Now this jet ski had mice living in it for ten years so idk what it is but I also don’t know how to get it out. Here’s a picture, lmk if I’m correct about this.

 

[Gwstaudy]

For some reason the picture didn’t show up in the last message. Here it is.

Could this be the cause of my problems?